import org.junit.Test;
import junit.framework.TestCase;
    public class MyUtilTest extends TestCase {
        @Test
        public void testNormal() {
            assertEquals("不及格", MyUtil.percentage2fivegrade(55));
            assertEquals("及格", MyUtil.percentage2fivegrade(65));
            assertEquals("中等", MyUtil.percentage2fivegrade(75));
            assertEquals("良好", MyUtil.percentage2fivegrade(85));
            assertEquals("优秀", MyUtil.percentage2fivegrade(95));
        }
        @Test
        public void testExceptions(){
            assertEquals("错误",MyUtil.percentage2fivegrade(105));
            assertEquals("错误",MyUtil.percentage2fivegrade(-55));
        }
        @Test
        public void testBoundary(){
            assertEquals("不及格",MyUtil.percentage2fivegrade(0));
            assertEquals("及格",MyUtil.percentage2fivegrade(60));
            assertEquals("中等",MyUtil.percentage2fivegrade(70));
            assertEquals("良好",MyUtil.percentage2fivegrade(80));
            assertEquals("优秀",MyUtil.percentage2fivegrade(90));
            assertEquals("优秀",MyUtil.percentage2fivegrade(100));
        }
    }